[Federal Register Volume 63, Number 11 (Friday, January 16, 1998)]
[Rules and Regulations]
[Pages 2596-2598]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-822]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-94-AD; Amendment 39-10285; AD 98-02-03]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 Mark 0100 and Mark 
0070 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Fokker Model F28 Mark 0100 and Mark 0070 series 
airplanes, that requires modification of the hook and latch engagement 
assemblies of the engine cowl doors, measurement of the aerodynamic 
mismatch between the fixed cowl and lower cowl door, and repair, if 
necessary. This amendment is prompted by reports of operational 
experience that indicate that an aerodynamic mismatch may exist between 
the fixed engine cowl and the lower cowl door, and may be the result of 
one or more hooks of the engagement assemblies not engaging adequately. 
This condition may cause the other hooks to carry loads higher than 
they were originally designed to carry, and could result in the failure 
of those hooks that are engaged. The actions specified by this AD are 
intended to prevent possible separation of the lower cowling from the 
airplane due to failure of the hooks of the engagement assemblies.

DATES: Effective February 20, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 20, 1998.

ADDRESSES: The service information referenced in this AD may be 
obtained from Fokker Services B.V., Technical Support Department, P. O. 
Box 75047, 1117 ZN Schiphol Airport, the Netherlands. This information 
may be examined at the Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Fokker Model F28 Mark 0100 
and Mark 0070 series airplanes was published in the Federal Register on 
November 5, 1996 (61 FR 56925). That action proposed to require 
modification of the hook and latch engagement assemblies of the engine 
cowl doors, measurement of the aerodynamic mismatch between the fixed 
cowl and lower cowl door, and repair, if necessary.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request to Extend the Compliance Time

    Two commenters request that the compliance time for accomplishing 
the proposed inspection specified in paragraph (a)(2) of the AD be 
changed from ``Within 2,500 flight cycles since the last inspection * * 
*'' to `` Within 2,500 flight cycles or 3,500 flight hours since the 
last inspection * * *, whichever occurs later.'' One of these 
commenters states that it is currently accomplishing the proposed 
inspection on its fleet of Fokker Model F28 Mark 0100 series airplanes 
during its regularly scheduled maintenance checks at 3,500 flight hour 
intervals. The commenter notes that the proposed 2,500 flight cycle 
inspection time may fall short of its currently scheduled 3,500 flight 
hour maintenance check.
    The FAA does not concur with the commenters' request to change the

[[Page 2597]]

compliance time. The FAA points out that the proposed compliance time 
of paragraph (a)(2) of the AD was developed in consideration of not 
only the degree of urgency associated with addressing the unsafe 
condition, but such factors as the manufacturer's and the foreign 
airworthinesss authority's [i.e., Rijksluchtvaartdienst (RLD)] 
recommendations, and the practical aspect of inspecting the affected 
airplanes within an interval of time that parallels normal scheduled 
maintenance for the majority of affected operators.
    Based on the average utilization rate of the worldwide fleet of 
Fokker Model F28 Mark 0100 series airplanes (approximately 1 flight 
hour per flight cycle), the request to include a 3,500 flight hour 
compliance time option, if granted, would be approximately equal to 
3,500 flight cycles. This option would result in a 1,000 flight cycle 
extension to the compliance time. The commenters have not provided any 
data to substantiate why extending the compliance time by approximately 
1,000 flight cycles would not compromise safety. However, under the 
provisions of paragraph (e) of the final rule, the FAA may approve 
requests for adjustments to the compliance time if sufficient data are 
submitted to substantiate that such an adjustment would provide an 
acceptable level of safety.

Service Bulletin Change Notification

    One commenter states that certain errors were found in the service 
information referenced in the proposed AD. Paragraph C.(2) of Part 2 of 
the Accomplishment Instructions of Fokker Service Bulletin SBF100-71-
019, dated March 21, 1996, should refer to Figure 5 (not Figure 4) for 
dimensions X and Y. Additionally, Figure 5 of the service bulletin 
should refer to Figure 6 (not Figure 5) for tool geometry.
    The FAA agrees with the commenter. Since issuance of the proposal, 
Fokker has issued Service Bulletin Change Notification (SBCN) SBF100-
71-019/1, dated February 28, 1997, which revises paragraph C.(2) of 
Part 2 of the Accomplishment Instructions of Fokker Service Bulletin 
SBF100-71-019 to correctly reference Figure 5 for dimensions X and Y. 
The final rule has been revised to reference SBCN SBF100-71-019/1, 
dated February 28, 1997, in addition to the previously referenced 
service information.
    In addition, the FAA has determined that the reference in Figure 5 
to Figure 5 (rather than Figure 6) for tool geometry is merely a 
typographical error, since paragraph C.(2) of Part 2 of the 
Accomplishment Instructions of Fokker Service Bulletin SBF100-71-019 
states ``As a reference, to obtain the correct measurements, use tool 
as shown in Figures 5 and 6.'' However, the FAA has forwarded 
information regarding this error to Fokker Services.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    The FAA estimates that 124 Fokker Model F28 Mark 0100 and 0070 
series airplanes of U.S. registry will be affected by this AD, that it 
will take approximately 3 work hours per airplane to accomplish the 
initial inspection and modification, and that the average labor rate is 
$60 per work hour. Based on these figures, the cost impact of the AD on 
U.S. operators is estimated to be $22,320, or $180 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

98-02-03  Fokker: Amendment 39-10285. Docket 95-NM-94-AD.

    Applicability: Model F28 Mark 0100 and Mark 0070 series 
airplanes as listed in Fokker Service Bulletin SBF100-71-019, dated 
March 21, 1996, as revised by Fokker Service Bulletin Change 
Notification SBF100-71-019/1, dated February 28, 1997; certificated 
in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.

    To prevent separation of the lower cowling from the airplane due 
to failure of the hook and latch engagement assembly of the cowl 
door, accomplish the following:
    (a) Accomplish the requirements of paragraph (b) of this AD at 
the latest of the times indicated in paragraphs (a)(1), (a)(2), and 
(a)(3) of this AD:
    (1) Prior to the accumulation of 2,500 total flight cycles; or
    (2) Within 2,500 flight cycles since the last inspection 
performed in accordance with Fokker Service Bulletin SBF100-71-003, 
dated April 14, 1989; Revision 1, dated August 8, 1989, or Revision 
2, dated November 21, 1994; or
    (3) Within 30 days after the effective date of this AD.

[[Page 2598]]

    (b) At the time specified in paragraph (a) of this AD, 
accomplish the actions specified in either paragraph (b)(1) or 
(b)(2) of this AD, as applicable:
    (1) For airplanes specified in Part 1 of Fokker Service Bulletin 
SBF100-71-019, dated March 21, 1996, as revised by Fokker Service 
Bulletin Change Notification SBF100-71-019/1, dated February 28, 
1997: Modify the hook and latch engagement assemblies of the left 
and right engine cowl doors, and inspect to determine the 
aerodynamic mismatch between the fixed cowl and lower cowl door; in 
accordance with Part 1 of the Accomplishment Instructions of Fokker 
Service Bulletin SBF100-71-019, dated March 21, 1996, as revised by 
Fokker Service Bulletin Change Notification SBF100-71-019/1, dated 
February 28, 1997.

    Note 2: Accomplishment of the modification of the hook and latch 
engagement assemblies of the left and right engine cowl doors, in 
accordance with Part 1 of the Accomplishment Instructions of Fokker 
Service Bulletin SBF100-71-003, dated April 14, 1989; Revision 1, 
dated August 8, 1989; or Revision 2, dated November 21, 1994; is 
considered acceptable for compliance with the applicable 
modification specified in paragraph (b)(1) of this amendment.

    (2) For airplanes specified in Part 2 of Fokker Service Bulletin 
SBF100-71-019, dated March 21, 1996, as revised by Fokker Service 
Bulletin Change Notification SBF100-71-019/1, dated February 28, 
1997, excluding those airplanes subject to paragraph (b)(1) of this 
AD: Perform a one-time inspection to determine the aerodynamic 
mismatch between the fixed cowl and the lower cowl door, in 
accordance with Part 2 of the Accomplishment Instructions of Fokker 
Service Bulletin SBF100-71-019, dated March 21, 1996, as revised by 
Fokker Service Bulletin Change Notification SBF100-71-019/1, dated 
February 28, 1997.
    (c) If the aerodynamic mismatch measured between the fixed cowl 
and lower cowl door is less than or equal to 4.5 mm, no further 
action is required by this AD.
    (d) If the aerodynamic mismatch measured between the fixed cowl 
and lower cowl door is greater than 4.5 mm, prior to further flight, 
perform a one-time inspection to measure the mis-engagement between 
the left and right engine hooks of the fixed cowl door and the 
clevis fittings of the lower cowl door; in accordance with Part 2 of 
the Accomplishment Instructions of Fokker Service Bulletin SBF100-
71-019, dated March 21, 1996, as revised by Fokker Service Bulletin 
Change Notification SBF100-71-019/1, dated February 28, 1997.
    (1) If the mis-engagement is less than or equal to 6.5 mm, no 
further action is required by this AD.
    (2) If the mis-engagement is greater than 6.5 mm: Within 1 year 
after measuring the mis-engagement required by this paragraph, 
modify the mid-clevis fitting on the right and left engine lower 
cowl door; in accordance with Part 3 of the Accomplishment 
Instructions of Fokker Service Bulletin SBF100-71-019, dated March 
21, 1996, as revised by Fokker Service Bulletin Change Notification 
SBF100-71-019/1, dated February 28, 1997. After accomplishment of 
this modification, no further action is required by this AD.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, International Branch, ANM-116, FAA, 
Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, International 
Branch, ANM-116.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (g) The actions shall be done in accordance with Fokker Service 
Bulletin SBF 100-71-019, dated March 21, 1996, as revised by Fokker 
Service Bulletin Change Notification SBF 100-71-019/1, dated 
February 28, 1997. This incorporation by reference was approved by 
the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Copies may be obtained from Fokker 
Services B.V., Technical Support Department, P.O. Box 75047, 1117 ZN 
Schiphol Airport, the Netherlands. Copies may be inspected at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.

    Note 4: The subject of this AD is addressed in Dutch 
airworthiness directive 1989-049/3 (A), dated June 28, 1996.

    (h) This amendment becomes effective on February 20, 1998.

    Issued in Renton, Washington, on January 7, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-822 Filed 1-15-98; 8:45 am]
BILLING CODE 4910-13-U